A lot of my light switches are just a single button these days. I have 4 events.
* Click - a quick down and up
* Hold - Button down for longer than 250ms.
* Release - button released after a hold.
* Double click - two clicks in short succession.
Do you actually find it convenient? I think I would hate it. I want my light switches plain and dumb: flick it upwards, lights on, downwards lights off, thanks, that's all, no thanks, I don't want to subscribe to your newsletter and connect my phone to it. I want proper real tactile feedback. I also want to be able to tell the state that the switch is in by looking at it to make sure it is off when, for example, there's a power outage and I need to leave.
Well, the buttons are added in addition to the switches. I don't mind there being a stuck on button beside the actual switch.
The other driver of this was adding smart bulbs as a "wiring free" automation option. Smart bulbs can only be communicated with if they have power. So the physical switches stay "on".
Now, when I have guests and they inevitably flick the switch, even thought the light came on automatically... it still works. It will initially make them frown that it seemed to come on but then went off again when they switched it. 99% of people will immeidately switch it the other way.
The net result, asides the slight confusion in the instant is the same as if the "automation" wasn't there. It is almost completely transparent to "OG use". Except maybe if they stand still too long it will switch it back off again.
In the hall ways, bathroom and kitchen there are no buttons. There is no need to have a button. The lights decide when to be on and when to be off. The concept of switching lights on or off has completely left my routine so much, when I walk into an non-automated room at night I pause for half a second and remember when the lights don't come on.
Other lights are harder to directly automate that way, like living rooms, bedrooms, offices etc. So they have buttons. Unimplemented yet, but the design I am hunting there is the time old state machine of "AUTO->OFF->AUTO->ON" on the "click". It's very easy to track that state machine with a boolean output (light on or not). When in "AUTO" mode they would respond like the hallway etc. Come one with motion and "exterior ambient light threshold" and automatically dim and warm after midnight with a 5 second slow start to save my eyes in the middle of the night. Yet a single press overrides into OFF or ON. Long press would toggle current state placing it into manual ON or OFF. Double click could do something else, like switch it's profile (the config that determines the various thresholds, delays, times of day, timeouts etc.)
There isn't really "an app". The only thing I occasionally need a "UI" for at all is maybe changing the living room light colours for a change. For that it's a generic open source web UI for zigbee2mqtt ... or I could use phillips hue or a dozen other off the shelf systems.
EDIT: While light automation obviously saves you the effort in teh first place... the real gem I found was the "after midnight" mode. If I get up in the middle of the night to go for a wizz, the automated hallway and bathroom lights will come on, detecting the motion. However, they will take 5 seconds to come up from black to 25% brightness. This is especially welcome in the pure shiny white tiled bathroom. The full bathroom lights at 3am is honestly painful. Not any more. "What if I need FULL light?", well, I just switch the bulbs power off and on again. That resets it to "power on state" which is 100% brightness. You will get about 10 seconds of that before the auto profile will dim it, but I'd class that a "missing feature" or a "bug" I should fix. After a power cycle the bulb should remain "manual" for a good 10 minutes maybe.